📦 长方体表面积Surface Area of a Rectangular Prism

使用说明与常见问题How-to & FAQ

「长方体表面积」是什么？What is the Surface Area of a Rectangular Prism tool?

表面积 = 2(lw + lh + wh)，同时给出侧面积 2h(l + w)、体积和体对角线长度。本地处理。Surface area = 2(lw + lh + wh), plus lateral area 2h(l + w), volume and space diagonal. Processed locally.

如何使用「长方体表面积」？How do I use the Surface Area of a Rectangular Prism tool?

填写长方体的长、宽、高，即可得到表面积 2(lw + lh + wh)、侧面积、体积和体对角线。结果会随输入实时更新。Enter the length, width and height to get the surface area 2(lw + lh + wh), the lateral area, the volume and the space diagonal. The result updates as you type.

正方体？A cube?

三边相等时表面积为 6a²。With all sides equal the area is 6a².

能举个计算实例吗？Can you show a worked example?

例如在「长方体表面积」中填 长 l = 3，宽 w = 4，高 h = 5，结果区显示：表面积：94；侧面积：70；体积：60；体对角线：7.071068For example, entering Length l = 3, Width w = 4, Height h = 5 in the Surface Area of a Rectangular Prism gives: Surface area: 94; Lateral area: 70; Volume: 60; Space diagonal: 7.071068

哪些输入会被检查？Which inputs are validated?

「长方体表面积」会检查这些输入——「长 l」、「宽 w」、「高 h」：必须填写，须大于 0；绝对值超过 10¹⁵ 的数也会被拒绝。不符合时结果区显示具体提示，不会给出数字。The Surface Area of a Rectangular Prism checks its inputs — "Length l", "Width w", "Height h": required, must be greater than 0; numbers above 10¹⁵ in absolute value are rejected too. When a value fails, the result area names the problem instead of showing a number.

有哪些选项可以调整？What options can I adjust?

「长方体表面积」的设置：「长 l」默认 3；「宽 w」默认 4；「高 h」默认 5。每次生成结果都按当前设置处理。Settings in the Surface Area of a Rectangular Prism — "Length l" default 3; "Width w" default 4; "Height h" default 5. The result always uses the current settings.

计算精度如何？How precise are the results?

「长方体表面积」使用 JavaScript 双精度浮点数（约 15–16 位有效数字）；极大或极小的数值可能存在精度误差。The Surface Area of a Rectangular Prism uses double-precision floating point (about 15–16 significant digits); very large or very small values may lose precision.

「长方体表面积」免费吗？需要注册吗？Is the Surface Area of a Rectangular Prism free? Do I need an account?

「长方体表面积」完全免费，无需注册或安装，打开网页即可使用，手机和电脑都能用；输入的内容只在你的浏览器本地处理。The Surface Area of a Rectangular Prism is completely free with no sign-up or install and works on phones and desktops; what you enter is processed only in your browser.